The invention pertains to the configuration of the longitudinal side of a vehicle with a door formed between two supporting vertical columns. In the case of a front-end or rear-end collision of the motor vehicle, the door serves as a brace between the columns acting in the longitudinal direction.
For safety reasons, modern motor vehicles are usually designed in such a way that their passenger compartment is as stable as possible, and the regions in front of and behind the passenger compartment are designed as crumple zones. Since the door openings are bounded in the longitudinal direction in the lower region only by the side sills and in the upper region by the roof lips, the vehicle doors for safety reasons are designed in such a way that they represent a reinforcement for the longitudinal columns. In the case of a front collision, for example, the A columns are supposed to be supported via the two front doors on the B columns so that the A columns do not buckle inward and make the passenger compartment smaller and narrower, which is dangerous for the space occupied by the vehicle passengers.
In practice, it has been found that vehicle doors can withstand the load sustained in case of an accident without significant deformation up to a maximum peak force. In the case of extremely serious accidents, this peak force is exceeded and then the doors may buckle out at a significant weak point or in the region of the center of the door and then can no longer transmit forces acting in the longitudinal direction. As a result, the integrity of the passenger compartment may be compromised because the sills and the roof lips are then also overloaded and buckle inward or are more or less strongly deformed. The doors then also usually can, in some occasions, not be opened.